Hi Carlos, 2010/3/29 Dane Springmeyer <[email protected]>: > First of all - really great approach. Summarizing your understanding as a > way to frame further questions is really helpful, so thanks for this effort.
+1 , great to see :) > - Adding a border to the map to show coordinates: I interpret this as > displaying a frame around the map that shows the longitude and latitude > coordinates. The more the map is zoomed in, the more exact the coordinates > will be. > may include non-geographic projections (ie. coordinates other than latitude & longitude). eg. New Zealand Transverse Mercator (http://spatialreference.org/ref/epsg/2193/) > > - Grids: I interpret this as displaying the longitude and latitude lines > over the map. likewise, the units may be in meters rather than degrees. > - Overlay images, including other PDFs: Does the 'overlay' concept have the > same meaning as in Google Maps? According to Google Maps' documentation, an > overlay is an object attached to a coordinate, like the markers used to > point to places > (http://code.google.com/apis/maps/documentation/mapplets/overlays.html#Markers). > If this is true, then this feature is about displaying these overlay images > on the exact points indicated by the associated coordinates (considering > that the units used for displaying on the screen and printing on a document > are different, am I right?). I'm not sure if I understand the part > 'including other PDFs', though. I was thinking adding other stuff to a "document". So maybe a watermark, legend, logo, version/id/user/date information, or having some way of fitting a map into a report. Isn't really a major, I think you can do that stuff with PDF tools (better to do it outside mapnik if its possible). > - Paper sizes/scale calculations: I read that images are displayed on paper > based on DPI units, so some calculations are needed to scale the maps to fit > different paper sizes. Tom Hughes mentions in the same thread that there are > some issues that need to be considered when tranlating the units used by > Mapnik and those of Cairo. > > Yes, these are core issues that should be worked out, tested, investigated > pretty early. I see you are playing around > with http://trac.mapnik.org/ticket/343, which is great. Also things like making sure the scale is a "round" number (eg. 1:1000, not 1:992.68), or specifying a fixed scale. One use case is being able to fit an extent inside an A3 sheet at either 1:1000, 1:5000, or 1:10000 scale, whichever is smallest. Mapnik doesn't need to do all that, just expose a way for the user to calculate things. > - Map layers as PDF layers: According to what I read, the objects displayed > on a PDF page can be organized in layers, which can be hidden. As a map is > rendered in layers, whose order is defined by a Mapnik configuration file > (http://trac.mapnik.org/wiki/XMLConfigReference), a PDF layer may be mapped > to a map layer. > > Yes, mostly. Basically most recent PDF viewers support the idea of layers, > such that users can turn various layers on and off, adding interactivity and > usefulness of the document, particularly when map data is included. Being > able to maintain the exact "<Layer>" elements created by a user authoring a > Mapnik XML file as "layers" in the resulting PDF file would be an excellent > thing, but potentially users would also want combinations of Mapnik > <Layer>'s to be exposed as PDF "layers". Ben's original work mapped Mapnik Layers to PDF Layers. Basically Adobe Acrobat reader has a layers panel when you open such a PDF, and you can show/hide layers. It was only for layers that were actually rendered by mapnik, so as Dane said, status=off layers wouldn't be in the PDF at all. Rob :) _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
